Assert that the newsletter doesn't contain relative urls
One-sentence description
The newsletter contains relative urls and thus is linking to the admin
Current behaviour / Reproducing the bug
- Create a newsletter
- Enter a url without http(s):// in content
- Send newsletter
- Open said url
- Links to django admin
Expected behaviour
No relative url in the newsletter. Thus checking for non-relative urls by checking if there are no mentions of the django admin in the eventual contents.